Comparison of cost-effectiveness of tuberculosis screening of close contacts and foreign-born populations

Although tuberculosis (TB) screening of immigrants has been conducted for o ver 50 yr in many industrialized countries, its cost-effectiveness has neve r been evaluated. We prospectively compared the yield and cost-effectivenes s of two immigrant TB screening programs, using close-contact investigation and passive case detection. Study subjects included all immigration applic ants undergoing radiographic: screening, already arrived immigrants requiri ng surveillance for inactive TB, and close contacts of active cases residen t in Montreal, Quebec, Canada, who were referred from June 1996 to June 199 7 to the Montreal Chest institute (MCI), a referral center specializing in respiratory diseases. For all subjects seen, demographic data, investigatio ns, diagnoses, and therapy were abstracted from administrative data bases a nd medical charts. Estimated costs of detecting and treating each prevalent active case and preventing future active cases, based on federal and provi ncial health reimbursement schedules, were compared with the costs for pass ively diagnosed cases of active TB. Over a period of 1 yr, the three progra ms detected 27 cases of prevalent active TB and prevented 14 future cases. As compared with passive case detection, close-contact investigation result ed in net savings of $815 for each prevalent active case detected and treat ed and of $2,186 for each future active case prevented. The incremental cos t to treat each case of prevalent active TB was $39,409 for applicant scree ning and $24,225 for surveillance, and the cost of preventing each case was $33,275 for applicants and $65,126 for surveillance. Close-contact investi gation was highly cost effective and resulted in net savings. Immigrant app licant screening and surveillance programs had a significant impact but wer e much less cost effective, in large part because of substantial operationa l problems.